diff --git a/lib/preprocessor.cpp b/lib/preprocessor.cpp
index 6c37e43a1..bdce31069 100644
--- a/lib/preprocessor.cpp
+++ b/lib/preprocessor.cpp
@@ -1380,19 +1380,13 @@ bool Preprocessor::match_cfg_def(const std::map<std::string, std::string> &cfg,
 }
 
 
-std::string Preprocessor::getcode(const std::string &filedata, const std::string &cfg, const std::string &filename)
+/**
+ * Get cfgmap - a map of macro names and values
+ */
+static std::map<std::string,std::string> getcfgmap(const std::string &cfg)
 {
-    // For the error report
-    unsigned int lineno = 0;
-
-    std::ostringstream ret;
-
-    bool match = true;
-    std::list<bool> matching_ifdef;
-    std::list<bool> matched_ifdef;
-
-    // Create a map for the cfg for faster access to defines
     std::map<std::string, std::string> cfgmap;
+
     if (!cfg.empty()) {
         std::string::size_type pos = 0;
         for (;;) {
@@ -1417,6 +1411,24 @@ std::string Preprocessor::getcode(const std::string &filedata, const std::string
         }
     }
 
+    return cfgmap;
+}
+
+
+std::string Preprocessor::getcode(const std::string &filedata, const std::string &cfg, const std::string &filename)
+{
+    // For the error report
+    unsigned int lineno = 0;
+
+    std::ostringstream ret;
+
+    bool match = true;
+    std::list<bool> matching_ifdef;
+    std::list<bool> matched_ifdef;
+
+    // Create a map for the cfg for faster access to defines
+    std::map<std::string, std::string> cfgmap(getcfgmap(cfg));
+
     std::stack<std::string> filenames;
     filenames.push(filename);
     std::stack<unsigned int> lineNumbers;
@@ -1596,7 +1608,7 @@ std::string Preprocessor::getcode(const std::string &filedata, const std::string
         ret << line << "\n";
     }
 
-    return expandMacros(ret.str(), filename, _errorLogger);
+    return expandMacros(ret.str(), filename, cfg, _errorLogger);
 }
 
 void Preprocessor::error(const std::string &filename, unsigned int linenr, const std::string &msg)
@@ -2445,7 +2457,7 @@ static bool getlines(std::istream &istr, std::string &line)
     return true;
 }
 
-std::string Preprocessor::expandMacros(const std::string &code, std::string filename, ErrorLogger *errorLogger)
+std::string Preprocessor::expandMacros(const std::string &code, std::string filename, const std::string &cfg, ErrorLogger *errorLogger)
 {
     // Search for macros and expand them..
     // --------------------------------------------
@@ -2453,6 +2465,19 @@ std::string Preprocessor::expandMacros(const std::string &code, std::string file
     // Available macros (key=macroname, value=macro).
     std::map<std::string, PreprocessorMacro *> macros;
 
+    {
+        // fill up "macros" with user defined macros
+        const std::map<std::string,std::string> cfgmap(getcfgmap(cfg));
+        std::map<std::string, std::string>::const_iterator it;
+        for (it = cfgmap.begin(); it != cfgmap.end(); ++it) {
+            std::string s = it->first;
+            if (!it->second.empty())
+                s += " " + it->second;
+            PreprocessorMacro *macro = new PreprocessorMacro(s);
+            macros[it->first] = macro;
+        }
+    }
+
     // Current line number
     unsigned int linenr = 1;
 
diff --git a/lib/preprocessor.h b/lib/preprocessor.h
index 2e881c518..b30587e28 100644
--- a/lib/preprocessor.h
+++ b/lib/preprocessor.h
@@ -130,10 +130,11 @@ protected:
      * expand macros in code. ifdefs etc are ignored so the code must be a single configuration
      * @param code The input code
      * @param filename filename of source file
+     * @param cfg user given -D configuration
      * @param errorLogger Error logger to write errors to (if any)
      * @return the expanded string
      */
-    static std::string expandMacros(const std::string &code, std::string filename, ErrorLogger *errorLogger);
+    static std::string expandMacros(const std::string &code, std::string filename, const std::string &cfg, ErrorLogger *errorLogger);
 
     /**
      * Remove comments from code. This should only be called from read().
diff --git a/test/testpreprocessor.cpp b/test/testpreprocessor.cpp
index 41842c189..dafef1de4 100644
--- a/test/testpreprocessor.cpp
+++ b/test/testpreprocessor.cpp
@@ -46,7 +46,7 @@ public:
         }
 
         static std::string expandMacros(std::string code, ErrorLogger *errorLogger = 0) {
-            return Preprocessor::expandMacros(code, "file.cpp", errorLogger);
+            return Preprocessor::expandMacros(code, "file.cpp", "", errorLogger);
         }
 
         static int getHeaderFileName(std::string &str) {
@@ -227,6 +227,7 @@ private:
         TEST_CASE(predefine1);
         TEST_CASE(predefine2);
         TEST_CASE(predefine3);
+        TEST_CASE(predefine4);
 
         // Test Preprocessor::simplifyCondition
         TEST_CASE(simplifyCondition);
@@ -2868,6 +2869,14 @@ private:
         ASSERT_EQUALS("\n\n\nFred & Wilma\n\n", actual);
     }
 
+    void predefine4() {
+        // #3577
+        const char code[] = "char buf[X];\n";
+        Preprocessor preprocessor(NULL,this);
+        const std::string actual = preprocessor.getcode(code, "X=123", "test.c");
+        ASSERT_EQUALS("char buf[$123];\n", actual);
+    }
+
     void simplifyCondition() {
         // Ticket #2794
         std::map<std::string, std::string> cfg;